Most Common Car Truck SUV Trouble Codes - Explaining OBD-II Codes

Hey, friends. It's Len here from 1A Auto. Today, we want to talk about something, maybe you're driving down the road, you happen to see a couple lights on your dash, you grab one of these little scanners, it's gonna start popping up some codes. What are those codes? Let's talk about some of the common ones that you might find.

Just keep in mind, this video is supposed to be short and sweet. If you need more information on diagnosing a particular code that we're gonna be listing in this video, make sure you check out the description below. We're gonna post links to each individual video. Now, the first code that I wanna talk to you about and keep in mind that these codes are in no particular order is a P0300, or P0300. That stands for a random or multiple cylinder misfire. Now, if you were to get this code, it's gonna come up with like I said, P0300. And it's more than likely gonna be accompanied with a couple other codes and it's probably gonna say something like P0301 or P0302. And those would be more specific codes. So, if you have this multiple cylinder misfire code, you'd want to obviously diagnose the other codes first because they can lead to this one. Some of the symptoms that you're probably gonna notice is, of course, the check engine light. And that's gonna be most common on almost all these codes because, well, why else would you be pulling the code? Another thing that you probably notice is when you're sitting idle, especially at maybe a red light or just sitting in a parking lot, you can feel your steering wheel shaking, maybe your butt's shaking, and the car is shaking a little bit. That's because your engine isn't firing right and it's just shaking around because it's not really off time, but the timing isn't right of the combustion and the exhaust and everything leaving the vehicle like it should.

And that leads us into the second set of codes that I wanna talk about. And yeah, they're a little bit the same as the first code that I was talking about because these have to do with direct cylinder misfires. You might pull that engine light code and you see you have a P0301. That essentially would mean that you have a misfire in cylinder one. You might also see P0302, P0303 and so on. Assuming you have a four-cylinder, will go all the way up to P0304. A six-cylinder would obviously be, you know, 306 and then so on, depending on if you have an eight-cylinder. With all that said, it's gonna be a more direction that you're gonna need to diagnose things. So, it tell you, "Maybe inside this cylinder one, P0301 has the issue."

Now, the third set of codes that I wanna talk to you about and I say codes because there's two that you might get, is a P0420 if you have a four-cylinder engine or a P0430 if you have a six or even maybe an eight-cylinder engine. What these codes are essentially gonna mean is you have an issue with your catalytic converter. The catalytic converter is part of your exhaust system. It's a small piece of your exhaust system, but it's gonna be the most expensive part of your exhaust system. What your catalytic converter does is it converts the type of pollutants that are coming out of your combustion chamber or from your engine before it gets sent out and into the environment. So, what it's gonna try to do, it's gonna try to burn up some of those hydrocarbons before they get sent out and pollute the environment essentially. Some of the symptoms that you're probably gonna realize if you do happen to have a bad catalytic converter is probably a funny smell, maybe a little eggy, you might notice that you have poor fuel economy all of a sudden, or maybe it's been diminishing over time, you might notice that you have a engine misfire, but for some reason, you don't have any issue with any of your maintenance items. And you might also notice a lack of power coming from the engine overall.

Okay. Now, the fourth code that I wanna talk to you about on this is a P0141. That's gonna stand for an O2 sensor heater circuit malfunction. And overall, it's gonna stand for a downstream O2 sensor. When I say downstream O2 sensor, I mean the one after the catalytic converter, which I just talked about in the last code. Now, the reason why you're probably gonna get this code is because your car's computer sends a little test down to that downstream O2 sensor. The downstream O2 sensor sends back a little code saying that it has a malfunction. Overall, it's probably gonna either be due to resistance, or even an incomplete circuit that has to do with that downstream O2 sensor. And if you're wondering about some of the symptoms of this aside from, of course, the check engine light on will be running rough or even decreased fuel economy.

The fifth code that I wanna talk to you about on this is a P0446. Essentially, what that comes down to is an issue with your EVAP system in your vehicle. And that also has to do with venting of your fuel system. To be specific, it actually really comes down to evaporative emission canister vent solenoid valve. I had to write it down because it's a big old set of words and, well, it's not that easy to remember. But anyway, like I said, it comes down to your fuel system and the way that it's able to be vented. If your system is getting clogged up with something such as like dust or dirt or debris, or maybe you just went out mudding or something like that, it's not gonna be able to vent properly, and you might find this code.

Now, for our sixth problem, we're gonna stay in that EVAP system, and this is gonna be a code P0455. When you get this code, what it's gonna come down to is a large EVAP leak. So, more than likely what that means is there's a problem with your gas cap. Maybe you take it off and you take a peek at that seal. If it looks like it's cracked, obviously replace it. Maybe take the seal off, give it a nice stretch. If you see any cracks, there you go. Other things that it could potentially be is maybe a hose is disconnected, maybe you've been doing some work. There's all sorts of things underneath there that could actually potentially cause it, but it all comes down to the EVAP system.

Now, the seventh code that I wanna talk to you about is a P0171 or a P0174. If you get either of these codes, overall, what it's gonna mean is your engine has a lean running condition. If you have a lean running condition, that means your engine is trying to burn too much air, as opposed to the amount of fuel that it's burning. Now, some of the symptoms that you might get for either of these codes might be your engine, of course, just plain old isn't running right, maybe it seems like it's coughing, just doesn't seem like it has enough power. Now, the cause for these codes could come down to two different things, either too much air or not enough fuel. There's a lot of things that could determine one of these causes though, maybe you have a bad fuel pump, bad mass airflow sensor, disconnected hoses. Could be a multitude of things. Make sure you check out the video.

Now, the eighth and the last code that I wanna talk to you about is a C0221. What this is essentially gonna mean is you have a problem in you're right front wheel speed sensor. Overall, it has to do with your ABS system. And ABS stands for anti-lock braking system. Now, cause for this issue, like I said has to do with that right front wheel speed sensor, whether it has to do with the cable that leads to the ABS or maybe even just the bearing itself.

Okay, friends, so that's pretty much the video I have for you today. If you need more information and you wanna continue diagnosing what we've talked about today, go ahead and click on the links in the videos below. If you liked the video, make sure you smash on that like button for me. It would mean the world. Please feel free to subscribe. And while you're at it, ring the bell that way there you can be kept up with all of our latest content. Thanks.